Bongo net – Page 5 – NOAA Teacher at Sea Blog

August 12, 2009April 6, 2021

Justin Czarka, August 12, 2009

NOAA Teacher at Sea
Justin Czarka
Onboard NOAA Ship McArthur II (tracker)
August 10 – 19, 2009

Mission: Hydrographic and Plankton Survey
Geographical area of cruise: North Pacific Ocean from San Francisco, CA to Seattle, WA
Date: August 12, 2009

Weather Data from the Bridge

Sunrise: 06:25 a.m.
Sunset: 20:03 (8:03 p.m.)
Weather: isolated showers/patchy coastal fog
Sky: partly cloudy
Wind direction and speed: North 10-15 knots (kt)
Visibility: unrestricted to less than 1 nautical mile (nm) in fog
Waves: northwest 4-6 feet
Air Temperature: 17.3 °C
Water Temperature: 16.6 °C

Science and Technology Log

Justin Czarka collects water samples to use in nutrient and chlorophyll research. While on the deck during “ops” (operation) all personnel must wear a life jacket and hardhat.

This log discusses the purpose behind the scientific cruise aboard the McArthur II. The cruise is titled, “Hydrographic and Plankton Survey.” The cruise is part of a larger study by many scientists to, in the words of chief scientist, Bill Peterson, “understand the effects of climate variability and climate change on biological, chemical and physical parameters that affect plankton, krill, fish, bird and mammal populations in Pacific Northwest waters.” This specific cruise focuses on hydrology, harmful algal blooms, zooplankton, krill, fish eggs, fish larvae, and bird and mammal observations.

I will provide an overview of these aspects of the cruise. The McArthur II is set up with sensors for salinity, temperature, and fluorescence that provide a continuous monitoring of the ocean (hydrology) throughout the cruise. In addition at various points along the transect lines (see the dots on the diagram of the cruise route on page 2), the CTD is deployed into the water column at specific depths to determine salinity (via measuring conductivity), water temperature, and depth (via pressure), and collect water samples (which we use to measure chlorophyll and nutrient levels at specific depths). The transects (predetermined latitudes that forms a line of sampling stations) have been selected because they have been consistently monitored over time, some since the late 1980s. This provides a historical record to monitor changes in the ocean environment over time.

The dots represent planned sampling station. Due to sea conditions, these have been slightly modified.

One scientist, Morgaine McKibben from Oregon State University, is researching harmful algal blooms (HAB). HABs occur when certain algae (the small plants in the ocean that are the basis of the food web) produce toxins that concentrate in animals feeding on them. As these toxins move up the food web through different species, they cause harmful effects in those species, including humans. Bill Peterson (NOAA/ Northwest Fisheries Science Center) and Jay Peterson (OSU/Hatfield Marine Science Center) are studying copepod reproduction. They are collecting data on how many eggs are laid in a 24 hour period, as well as how the copepod eggs survive in hypoxic (low oxygen) conditions. Mike Force, the bird and marine mammal observer is keeping a log of all species spotted along the cruise route, which is utilized by scientists studying the species.

Personal Log

Tiny squid collected in a vertical net and viewed under microscope on Crescent City transect line at 41 deg 54 min North.

Who said you never find the end of the rainbow? All you have to do is go out to sea (or become a leprechaun!). We have been going through patches of fog today, putting the foghorn into action. When it clears out above, yet is foggy to the horizon, you get these white rainbows which arc down right to the ship. We have become the pot of gold at the end of the rainbow. Who knew it was the McArthur II! If you follow the entire rainbow, you will notice that it makes a complete 360° circle, half on top the ocean and half in the atmosphere near the horizon.

I enjoyed using the dissecting microscope today.

The water collected from the vertical net is stored in a cooler on the deck to be used in experiments. I was able to collect a sample of the water, which contained a diverse group of organisms, from tiny squids to copepods to euphausiids. These tiny organisms from the size of a pinhead to a centimeter long are critical to the diets of large fish populations, such as salmon. Under magnification, one can see so much spectacular detail. I have learned how essential it is to have an identification guide in order to identify the names of each copepod and euphausiid. On the other hand the scientists tend to specialize and become very adept at identifying the different species.

Animals Seen Today

Arrow worms (long clear, with bristles)
Shrimp Copepods
Tiny rockfish (indigo colored eyes)
Fish larvae

August 11, 2009April 6, 2021

Justin Czarka, August 11, 2009

NOAA Teacher at Sea
Justin Czarka
Onboard NOAA Ship McArthur II (tracker)
August 10 – 19, 2009

Mission: Hydrographic and Plankton Survey
Geographical area of cruise: North Pacific Ocean from San Francisco, CA to Seattle, WA
Date: August 11, 2009

Weather data from the Bridge

Sunrise: 6:25 a.m.
Sunset: 20:03 (8:03 p.m.)
Weather: partly cloudy
Sky: patchy fog
Wind direction and speed: Northwest 5-10 knots
Visibility: unrestricted to less than 1 nautical mile (nm) due to fog
Waves: 5-7 feet
Air Temperature: 15° Celsius
Water Temperature: 12.92 °Celsius

Science and Technology Log

The McArthur II took about six hours from leaving port in San Francisco to reach our first station at Bodega Bay. We arrived at Bodega Bay around midnight. Bodega Bay, along with the next three stations, Point Arenas, Vizcaino Canyon, and Trinidad Head, California, will be sampled at only one station location each as we move up the coast to reach our first transect line of nine stations off Crescent City, California (Latitude: 41 deg 54 min). Due to leaving port later than expected, the science team has dropped some of the sampling sites at the southern end of the cruise. Still we are sampling as we head north in order to get an enhanced survey picture along a north-south line. At the stations, we are dropping the CTD into the water column, using the vertical net, and the bongo net.

Jennifer Menkel and Lacey O’Neal observe the CTD deployment. The left screen display depth sounds on three different frequencies, the middle screen creates graphs based on the CTD sensors, and the right screen shows live video feed of the CTD deployment on the fantail (back deck) of the McArthur II.

While I did not participate in the first sampling at Bodega Bay, my shift (read more about shifts below) began sampling at Point Arenas and then Vizcaino Canyon. Upon entering the dry lab, Jay Peterson and Jennifer Menkel, both of Oregon State University, Hatfield Marine Science Center (OSU/HMSC) in Newport, Oregon, were observing the data stream for the CTD on the computer monitors with McArthur II senior survey technician Lacey O’Neal. Communication is essential. The scientists are looking at the TV monitors for the CTD deployment outside, altimeter (measures the CTD’s height above the seafloor), depth below the surface, and communicating with both the ship’s officers on the bridge, who are navigating the boat, and crew who are working the winches. Everyone has to work together to ensure that the CTD is deployed and retrieved safely. Otherwise, it could potentially hit the ship, causing damage to the ship, crew, and/or CTD sensors. I am appreciating the emphasis on collaboration that occurs for the benefit and safety of the scientific research occurring on the ship.

I will discuss the sample collection technique for the chlorophyll. The main purpose for measuring the chlorophyll is to determine the chlorophyll composition and suitability for single celled algae to develop. These single celled organisms are the basis of the food chain. By determining the amount of chlorophyll, you can look at the probability of organisms to develop at that location, such as plankton. Plankton succeed where there is enough light to allow photosynthesis to occur. Deni Malouf, a marine science technician from the U.S. Coast Guard, and I put on waders, boots, life jackets, gloves and hardhats. We headed out to the CTD to collect water samples from specific depths. After filling up brown bottles (which prevent exposure to sunlight) with water, we transferred the bottles to the wet lab to pour 100 mL through a filter that collects chlorophyll on top while allowing the water to flow through by utilizing a vacuum. This procedure is done while ensuring that the equipment, filters, and water samples avoid contact with your hands, thus contaminating the sample. After the water has been filtered the filter is placed in a centrifuge tube (vial) with tweezers, covered to avoid exposure to light, and stored in the freezer for lab analysis at a later date. The sample is covered to prevent exposure to sunlight. If not, sunlight could cause more chlorophyll to develop, which would be an inaccurate reading for how much chlorophyll was actually collected at specific depths in the water column at a sampling station.

I am measuring a 100 mL water sample to collect chlorophyll on a filter inside the black cups in the wet lab. These containers have a filter that at the bottom. A vacuum draws the water through white tube, leaving the chlorophyll behind on the filter.

Personal Log

The work conducted aboard the McArthur II, as well as other ships in the NOAA fleet, revolves around a schedule of watches (a watch is a shift). Crewmembers work on the McArthur II in four or eight hour watches. The time of day and length vary for different crewmembers. As for the science team, Bill Peterson, our chief scientist (cruise leader) from NOAA/ Northwest Fisheries Science Center (NWSC), Newport, Oregon, arranged us into 12-hour watches. There is a day watch and night watch. I am part of the day watch, which commences at 7:00 a.m. and ends at 7:00 p.m. You muster (show up) about a half hour before your watch begins so that the previous watch knows you are ready to begin work, and to assist as needed with the end of the previous watch. My watch is comprised of Jay Peterson, Jennifer Mendel, and myself. There is a lot of teamwork and cooperation within the watches. Even this morning, Deni Malouf, who had been working the night watch, stayed on for a portion of the day watch to assist me with the protocol for filling up the water samples from the CTD, for preparing chlorophyll samples, and for setting up the Niskin bottles on the CTD to be deployed at the next station.

Vocabulary

*Dry lab- in the back of the O-1 deck (one of the floors on the ship above the waterline) where the computer equipment is situated. Used to monitor CDT deployment.*

*Wet lab-an indoor lab in the back of the O-1 deck connected where water samples are tested. Contains sinks, freezers, refrigerators, and science equipment.*

*Vertical net- a net deployed vertically through the water column at one specific location. Has a weight on the bottom of it to maintain its shape on the way through the water column.*

Bongo net- a net for collecting organisms, that appears to look like a set of bongo drums. Attached to a cable and the J frame, deployed off the side of the boat, and collects samples as the boat trawls at a specific speed to maximize the collection.

September 11, 2008April 2, 2021

Mary Anne Pella-Donnelly, September 11, 2008

NOAA Teacher at Sea
Mary Anne Pella-Donnelly
Onboard NOAA Ship David Jordan Starr
September 8-22, 2008

Mission: Leatherback Use of Temperate Habitats (LUTH) Survey
Geographical Area: Pacific Ocean –San Francisco to San Diego
Date: September 11, 2008

Weather Data from the Bridge
Latitude: 3647.6130W Longitude: 12353.1622 N
Wind Direction: 56 (compass reading) NE
Wind Speed: 25.7 knots
Surface Temperature: 15.295

Bongo net being deployed to collect specimens

Science and Technology Log

One oceanographic phenomena of interest is the deep scattering layer (DSL). This is a zooplankton and micronekton rich layer that is found below the depth that light penetrates to in the daytime. After sunset, this DSL layer migrates up closer to the surface. In some locations the daytime DSL may be at a depth of 225-250 m depth in this area of the California current ecosystem, and 0-100 m during the night. It is hypothesized that the organisms stay deeper down during the daytime to avoid predation, and move up toward the surface at night when it is safer from predators. Oceanographers take advantage of this information. Every evening, two hours after sunset, bongo nets are deployed to a depth of 200m and then slowly brought to the surface to get a sample of the entire water column. The purpose is to collect samples of those organisms that are found in the DSL. During the day these organisms would be much deeper down below the surface, but at night they are much closer.

Chart that converts wire length and angle to depth

The process begins with opening up the large plankton nets and attaching a weight in between the loops of the frame. The frame is hooked to a cable that is maneuvered by a winch operator. After the bongo net is swung out from the ship, a large protractor, an inclinometer, is attached. This is used to give the Officer of the Deck (OOD) driving on the bridge an indication of speed needed to deploy the net at. The OOD adjusts the speed of the ship to maintain the required angle, which allows the net to remain open for collection and reach the desired depth. Looking at the chart above, you can see that the angle the wire is deployed at, along with the amount of wire paid out, can be converted to a given depth. Trigonometry at work. There is also a flow meter attached inside each of the bongo loops. The readings from this give an indication of the volume of water that passed through the nets. When the bongo is retrieved, before the end is detached, each net is rinsed with salt water from a hose in order to retrieve as much of the sample as possible in the cod end. This end is detached and brought into the lab. One of the samples is examined in the lab, for relative types, while the other sample is preserved in formaldehyde and sodium borate for later examination and identification.

Personal Log

It is very interesting being rocked to sleep each night. Being on the top bunk, I am about 2 feet from the ceiling, with several pipes suspended from the ceiling. Once settled in bed, there is little opportunity to move around much. But being slowly rocked from side to side is a very interesting sensation, and is relaxing. It is becoming easier to tell how calm the water is that the ship is moving through, or a little about the weather, since sometimes we rock up and down, instead of from side to side. We were told that when it gets really rough it is a good idea to place a life jacket under the edge of the mattress to keep us from falling out. Each bed has a dark curtain edging it, since many of the crew and scientists may have opposite shifts. Since there is no porthole in my stateroom, when the lights are out and the curtain is closed, it is very dark. It would be impossible to tell night from day, except by an internal clock or a timepiece. It has been comfortable sleeping. Getting up is the only difficult part, maneuvering in the small space of the bunk and being careful not to disturb my bunkmate, Liz. Her schedule varies from mine, due to her bongo net responsibilities and CTD expertise. So far the sleeping arrangement has worked out well.

Words of the Day

Distribution: the local species and numbers of organisms in an area; Biomass: the combined mass of a sample of living organisms; Micronekton: free swimming small organisms; Zooplankton: small organisms that move with the current; Predation: the process of organisms eating other organisms to survive; Inclinometer: protractor designed to measure altitude from the horizon.

Questions of the Day

What organisms do you know of that change their feeding strategy at different times of the day?
In the local creek, river, or lake near you, are there both micronekton and zooplankton? How could you find out?

August 16, 2008April 5, 2021

Rebecca Bell, August 16, 2008

NOAA Teacher at Sea
Rebecca Bell
Onboard NOAA Ship Delaware II
August 14-28, 2008

Mission: Ecosystems Monitoring Survey
Geographical Area: North Atlantic
Date: August 16, 2008

Weather Data from the Bridge
Time: 1807 (GMT)
Latitude: 36.05.40 N Longitude: 75.24.30 W
Air Temp ⁰C: 25.3 ⁰C
Sea Water Temp: 26.7 ⁰C

On left: small barrel-shaped copepods; Center: white, arrow worms; Top right: amphipods

Science and Technology Log

The most common zooplankton we have seen so far are salps, amphipods, arrow worms and copepods. Pteropods (sea butterfly) have been in a number of samples but are not numerous. Salps look like clear, jelly-like marbles. We’ve encountered these animals in warm, shallow water. They are holoplanktonic relatives of sea squirts (Urochordata). Salps are filter feeders, using cilia to move suspended particles from the water. They feed by pumping water through a sieve to remove bacteria and nanoplankton, and are thus, a very important link in the food chain. Some species of salps form huge chains by budding. They show both sexual and asexual life stages. For more about salps and photos see this website.

Amphipods are also extremely common crustaceans. There is no carapace (shell-like covering), but their bodies are flattened side-to-side, much like a shrimp. Their bodies are segmented with 6 segments in the head, 8 in the thorax and 6 in the abdomen.¹ They have a brood pouch on their thoracic limbs. They have a variety of limbs used for feeding, crawling or jumping. One group lives off a host, feeding on salp tissues. Some types live in tubes; others use their back legs to anchor themselves while they sway to and fro in the water column. Some species swim rapidly while others stay near the bottom of the ocean. Many will move vertically in the water column, moving near the surface during the day, and sinking again at night. The species we are catching has large compound eyes that can be seen by the naked eye. For more about amphipods, visit this website.

Becky examines the catch using a hand lens.

Copepods are very common crustaceans, with more than 200 species and 10,000 families. ²We have found more of these than any other organism. Copepods are omnivorous. Some groups graze on microplankton; other groups of copepods prey on larger plankton, including other copepods. They are an important link in the food chain as well, moving carbon from a microscopic level to a larger trophic (feeding) level. They are eaten by jellyfish, fish, comb jellies and arrow worms. Copepods have “antennae” that have special sensors that detect water movement around them. They are able to move toward prey by contracting a muscle that runs in a circle around their bodies. For more about copepods, visit this website.

Arrow worms (Chaetognatha) are common along coasts, but we did not catch any out away from shore. Arrow worms are classified in their own group, distinct from Annelids (earthworms), round worms and flatworms, which are all separate groups of worms. They are predators, often waiting to ambush their prey. When their cilia detect prey, usually copepods, the arrow worm contracts 2 muscles that run dorsally and ventrally (top to bottom) to strike. Their mouths have spines that grab the prey and smaller “teeth” produce a venom that subdues the prey. The prey is swallowed whole. Arrow worms, in turn, are eaten by jellyfish, copepods and fish.²

Sea Butterflies were not common, but they are very interesting. Sea butterflies (pteropods) are holoplanktonic mollusks, related to snails. Basically, they are shell-less snails. Their foot is modified into winglike structures (ptero= winged) that they flap as they swim through the water. Their bodies are tube-shaped and clear. The bodies and wings of the species we have seen are an orange-pink color. They are predators and are preyed upon by fish, sea birds and whales.

NOAA Photo Library, Sea Butterfly
Photo Sea Butterfly photo
Sea Butterfly and other photos

References:

Information for these paragraphs were modified and combined from the following sources: ¹Newell, G.E. and Newell, R.C.; Marine Plankton: A Practical Guide; 5th edition; 1977; Hutchinson & Co; London.²Johnson, William S. and Allen, Dennis M.; Zooplankton of the Atlantic and Gulf Coasts: A Guide to Their Identification and Ecology; 2005; Johns Hopkins University Press.

Personal Log

This morning we saw dark clouds in the distance. You could see rain falling from the clouds. Nearby we could see the tail of a water spout disappearing into the clouds. We sampled our southern-most station and are now heading north along the coast just south of Chesapeake Bay. The samples we are pulling now have a lot of diatoms.

August 15, 2008April 5, 2021

Rebecca Bell, August 15, 2008

NOAA Teacher at Sea
Rebecca Bell
Onboard NOAA Ship Delaware II
August 14-28, 2008

Mission: Ecosystems Monitoring Survey
Geographical Area: North Atlantic
Date: August 15, 2008

Weather Data from the Bridge
Latitude: 3846.7 Longitude: 7302.1
Temp 25.4 C

Science and Technology Log

In the last post, I explained WHY we are collecting zooplankton. This post will illustrate HOW the samples are taken.

The samples are collected using a device called a bongo net (Yes, like the musical instrument). You can see the metal rings and the nets hang from the metal rings. One net is marked with red and the other green. This allows you to tell the two nets apart. The samples from the red side will be used for the ichthyoplankton study. The samples from the green side will be used for the zooplankton study.

The white device is the CTD (Conductivity, Temperature, Depth). You attach it to the bongo net frame and turn it on. The CTD takes measurements on the way into the water and on the way out of the water. When the bridge clears you, the computer operator (inside) tells the hydraulics operator to start letting out the line and at what speed to let it out and bring it in. You calculate the amount of time in and out using a chart that is based on changing depth. You have to calculate it so you get at least a 5-minute tow.

Now the bongo nets are raised on the A-frame. You can see the CTD above the bongos (right picture) and there is a lead weight beneath and between the nets. Next, the A-frame moves the nets over the side of the ship and they are lowered into the water. You cruise for at least 5 minutes. The idea is to get within 5 meters of the bottom, then start bringing the nets back in. The computer operator keeps track of where the bottom is. The idea is to stop the line going out in time so the nets don’t hit the bottom and pull up a bunch of sand. Then you just have to wait for the tow, and eventually for the nets to come back up.

The bongos are removed from the A-frame and brought into the wet lab. You use the hose to wash the plankton down to the bottom of the net. The bottom of the net is put into the sieve. When the net is hosed down to the sieve end, you untie the bottom of the net and let the plankton wash into the sieves. The mesh captures zooplankton, but lets smaller phytoplankton through. Finally you rinse the plankton from the sieves into a jar with 5% formalin for preservation. A label is put into the jar as well as on top of the jar, stating station number, date and time.

NOAA Teacher at Sea, Becky Bell, assists in deploying the bongo nets.

Personal Log

We had a fire drill and an “abandon ship” safety drill. In the picture to the right, I am wearing a survival suit, lovingly known as a “Gumby suit”. If you abandon ship, you have to run to the deck and put on this suit. It is one piece, with inflatable neck rest, whistle and flashing pocket light so you can be spotted. You have to lay the suit out on deck, and sit down in it. Feet go in first, then you stand up and pull the rest over your head, find the arms etc. Look at the look on my face. Not too sure about this! The front flap closes to show only your eyes–on me a little higher. You should try zipping the front zipper with thick rubber gloves that are too big for you. It reminds me of the astronauts trying to fix the space station. I have a new appreciation for how difficult it is too, like, HOLD anything. The best news yet–we get to practice next week again.

The nets begin to emerge from the water.

Becky waits for the nets to come back up after the tow — Waiting for the nets to come back up after the tow

Then she puts the plankton into a jar for preservation — Then she puts the plankton into a jar for
preservation

Becky dons her survival suit during a safety drill.